1. Department of Epidemiology, University of North Carolina at Chapel Hill, NC, USA,
2. Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, MD, USA,
3. Department of Epidemiology and Biostatistics, University of South Carolina, Columbia, SC, USA,
4. Division of Epidemiology, School of Public Health, University of California, Berkeley, CA, USA,
5. Division of Gastroenterology and Hepatology, University of North Carolina at Chapel Hill, NC, USA,
6. Department of Chronic Disease Epidemiology, Yale School of Public Health, Newhaven, CT, USA,
7. Program in Epidemiology, Fred Hutchinson Cancer Research Center, Seattle, WA, USA and
8. Keck School of Medicine, University of Southern California, Los Angeles, CA, USA